Flea bites are not usually infected with disease. A few may experience localized skin irritation, redness, infection with pathogenic bacteria, etc. Fleas bite people by sucking blood, but the amount of blood is very small, so generally do not spread diseases through blood, such as the common hepatitis B syphilis, AIDS, hepatitis C is generally not transmitted through fleas. Fleas will secrete toxins while biting, and a few people may experience localized itching, redness and swelling of the skin, and some people with low resistance may also induce localized skin infections. Fleas in certain areas may carry pathogens, such as hemorrhagic fever virus, plague bacillus, etc. Fleas can act as a vector for viruses, and flea bites may be infected with the corresponding pathogens. After being bitten by fleas, it is important to closely observe the reaction of the human body and consult a doctor promptly if you feel unwell.